Roller device and electronics using the roller device

ABSTRACT

A roller device includes a motor and a speed reducer inside a cylindrical roller or arranged coaxially, and an electronic apparatus includes a printer using the roller device. This roller device comprises a motor ( 5 ) disposed on a cylindrical roller ( 2 ), a sun gear ( 7 ), planet gears ( 8 ), a first inner tooth gear ( 10 ) provided inside of the cylindrical roller ( 2 ), and a second inner tooth gear ( 11 ) provided inside of a bearing element ( 12 ). The rotation of the bearing element ( 12 ) is suppressed by a predetermined force. Thus the rotation of the motor ( 5 ) is decelerated, and the cylindrical roller is rotated at a reduced speed. By rotating the bearing element with a force greater than a predetermined force, the cylindrical roller can be rotated manually.

TECHNICAL FIELD

The present invention relates to a roller device as a paper feeder for aprinter or the like, and an electronic apparatus such as printer usingthe roller device.

BACKGROUND ART

In a conventional electronic apparatus including a printing unit such asa printer, in most cases, a roller for feeding paper is arrangedparallel with a motor for driving the roller and some of the gears forreducing the rotating speed of the motor. This is because the rotationof the motor needs to be transmitted to the roller after the speed isreduced, from the driving gear fixed to the motor through plural drivinggears arranged in parallel thereto. As a result, the size of the entireprinter becomes large.

Recently, however, as the printers and other electronic apparatuses arebecoming smaller and smaller in size, the driving mechanism ofcylindrical roller is required to be reduced in size. For example, hasbeen proposed to incorporate a driving mechanism in the cylindricalroller as disclosed in Japanese Laid-open Patent No. 2-22635. Thispublication discloses a cylindrical roller with both ends being open, amotor accommodated at one end in this cylindrical roller, a sun geardisposed on the shaft of the motor in the cylindrical roller, planetgears engaging with the sun gear in the cylindrical roller, acylindrical roller having a first inner tooth gear provided at the innerside of the cylindrical roller opposite to the planet gears and having asecond inner tooth gear fixed to the motor and engaging the planetgears, and a drive mechanism thereof.

In this example, the second inner tooth gear is fixed to the motor.Therefore, the cylindrical roller cannot be rotated manually (ifrequired) when feeding paper or setting paper. In other words, the firstinner tooth gear of the cylindrical roller engages the second innertooth gear through the planet gears. However, the second inner toothgear is fixed to the motor. This motor is fixed to the fixing unitoutside of the opening at one end of the cylindrical roller. Thecylindrical roller cannot be turned manually and if it is attempted toturn the roller by force, the planet gears and the first and secondinner tooth gears will be broken.

Meanwhile, the conventional electronic apparatus of this kind comprises,in most cases, a main body case, a sheet receiver disposed in the mainbody case, a roller for holding the printing sheet together with thesheet receiver, and a head for recording information on the printingsheet in the main body. Therefore, the roller is rotated while theprinting sheet is being held between the roller and the sheet receiver.Thus, the printer supplies the printing sheet into the head unit, anddischarges the printing sheet on which the information is recorded bythe head to outside of the main body case. In this configuration, aftera change of sheets, for example, it is predicted that the operation ofthe roller may not be secure as mentioned below.

When changing sheets, the roller needs to be separated from the sheetreceiver by disconnecting the roller and a driving element such as amotor disposed outside of the roller. Therefore, in most cases hitherto,the roller and the driving element were coupled by plural gears. Bydisconnecting these gears, the roller can be separated from the sheetreceiver.

After changing the sheets, when holding the printing sheet between theroller and sheet receiver again, the plural gears engage each other, andare coupled. The gears can engage smoothly as long as the tops andbottoms of the teeth are appropriately facing, each other. However, thetops and bottoms of the teeth are not always facing appropriately, andthe gear may be deformed due to mutual collision between tops. Thus, thesubsequent power transmission, that is, the roller operation may not besecure.

SUMMARY OF THE INVENTION

It is hence an object of the invention to prevent damage to the planetgears, and first and second inner tooth gears when manually rotating thecylindrical roller used in a printer or the like.

It is another object of the invention to feed the printing sheetmanually by manually rotating the cylindrical roller.

It is a further object of the invention to present an electronicapparatus including a printer having a compact design.

It is still another object of the invention to present an electronicapparatus including a printer for operating the roller securely.

To achieve these objects, the roller device of the present inventionincludes a cylindrical roller with both ends open, a motor having amotor shaft accommodated at one end in the cylindrical roller, a sungear disposed on the motor shaft in the cylindrical roller, and planetgears engaging the sun gear in the cylindrical roller. A bearing elementhas a first inner tooth gear provided at the inner side of thecylindrical roller opposite to the planet gears, and has a second innertooth gear engaging the planet gears, and at least a support shaft ofthe bearing element is disposed at another end of the cylindricalroller. A bearing mechanism supports the cylindrical roller rotatably onthe bearing element. At one end of the cylindrical roller, a fixing unitof the motor is provided, and the rotation of the second inner toothgear is defined by a predetermined force.

According to this configuration, the cylindrical roller can be rotatedby the rotating force of the motor, at a rotating speed and torqueadequate for feeding paper. In addition, when a rotating force more thana specified value is applied to the cylindrical roller or the supportshaft of the bearing element in their rotating direction, the supportshaft of the bearing element rotates the cylindrical roller by way ofthe second inner tooth gear, planet gears, and first inner tooth gear.As a result, the printing sheet can be fed manually. Thus, the printingsheet can be fed manually without damage to the planet gears or firstand second inner tooth gears. The electronic apparatus including theprinter device having such roller device presents a printer having acompact design, and operates the roller securely.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a cylindrical roller device in a firstembodiment of the invention.

FIG. 2 is a perspective exploded view of the cylindrical roller devicein the first embodiment.

FIG. 3 is a sectional view of a cylindrical roller of the invention.

FIG. 4 is a perspective exploded view of a cylindrical roller portion ofthe invention.

FIGS. 5A and 5B are essential sectional views of a cylindrical roller ofthe invention.

FIGS. 6A and 6B are essential side views of a cylindrical roller of theinvention.

FIG. 7 is an essential sectional view of a second embodiment of theinvention.

FIG. 8 essential side view of the second embodiment of the invention.

FIG. 9 is an essential sectional view of a third embodiment of theinvention.

FIG. 10 is an essential sectional view of a fourth embodiment of theinvention.

FIG. 11 is an essential side view of the fourth embodiment.

FIG. 12 is an essential sectional view of a fifth embodiment of theinvention.

FIG. 13 is an essential perspective view of the fifth embodiment.

FIG. 14 is an essential perspective view of a sixth embodiment of theinvention.

FIG. 15 is an essential sectional view of the sixth embodiment.

FIG. 16 is an essential sectional view of the sixth embodiment.

FIG. 17 is a sectional view of a cylindrical roller device in a seventhembodiment of the invention.

FIG. 18 perspective exploded view of the cylindrical roller device inthe seventh embodiment.

FIG. 19 is a perspective view of a printer in the seventh embodiment.

FIG. 20 is a perspective exploded view of the printer in the seventhembodiment.

FIG. 21 is another perspective exploded view of the printer in theseventh embodiment.

FIG. 22 is a perspective view of a printer in an eighth embodiment ofthe invention.

FIG. 23 is a sectional view of the printer in the eighth embodiment.

FIG. 24 is a sectional view with an open lid of the printer in theeighth embodiment.

FIG. 25 is an essential sectional view with an open lid of the printerin the eighth embodiment.

FIG. 26 is an essential perspective view of a printer in a ninthembodiment of the invention.

FIG. 27 is a sectional view with an open lid of the printer in the ninthembodiment.

FIG. 28 perspective exploded view of a cylindrical roller device in atenth embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A first embodiment of the invention is described below by referring tothe accompanying drawings. In FIG. 1 and FIG. 2, a cylindrical roller 2is supported on a U-shaped base body 1 made of metal plate. Thecylindrical roller 2 is, as shown in FIG. 3, formed by covering theouter circumference of a cylinder 3 (made of metal such as aluminum)with a cylinder 4 (made of an elastic material such as silicone rubber).

In the cylindrical roller 2, a motor 5 is accommodated in a contact-freestate. A sun gear 7 is coupled to a motor shaft 6 of the motor 5 asshown in FIG. 4. The sun gear 7 engages two planet gears 8. The twoplanet gears 8 are supported on a carrier 9 at a specific interval. Thesun gear 7 engages the planet gears 8 from the inside.

A motor end portion of both of the planet gears, in turn, engage a firstinner tooth gear 10 provided on an inside surface of the cylinder 3. Asecond inner tooth gear 11 engages a free-end portion of both planetgears 8 (i.e., an end opposite the motor-end).

The second inner tooth gear 11 is provided on the inner surface of acap-shaped bearing element 12. A support shaft 13 is integrally providedon the bearing element 12 at an opening of cylinder 3 so that thesupport shaft 13 is located at a side of the bearing element 12 oppositethe motor 5.

A shaft 9 a of the carrier 9 is rotatably supported in a bottom recess12 a of the cap-shaped bearing element 12. The motor 5 is held by asupport element 14. At a first open end of the cylinder 3, this supportelement 14 is fixed to a plate element 18 folded upward at a side of thebase body 1 shown in FIG. 1 and FIG. 2. On the outer periphery of thesupport shaft 13 and support element 14, a bearing mechanism 15 isprovided as shown in FIG. 3, and the cylinder 3 is rotatably supported.As shown in FIG. 4, a power feed line 16 is drawn inside of the cylinder3 from outside of the cylinder 3 through a hollow space in the supportelement 14 for feeding power from outside of the cylinder 3 into themotor 5.

In a cylindrical roller with this type of a configuration, the number ofteeth of the first inner tooth gear 10 should be, for example, 36, andthe number of teeth of the second inner tooth gear 11 should be 34. Thesun gear 7 rotates, and the planet gears 8 revolve around the sun gear7. Since the two planet gears 8 engage the first inner tooth gear 10 andthe second inner tooth gear 11, a rotation difference of two teeth(i.e., a deviation) occurs in one revolution of the planet gears 8.]

The support shaft 13 connected to the second inner tooth gear 11penetrates through the plate member 18 a having a through-hole 17 asshown in FIG. 1, FIG. 2, and FIG. 5A. On the outer circumference of aflat portion 13 a of the support shaft 13, a rotation suppressor 19 a isintegrally formed on a rotation knob 19 made of synthetic resin. Thisrotation suppressor 19 a has a polygonal, (specifically octagonal) outercircumference as shown in FIG. 6A. A free end of a plate spring 20 ispressed against the outer circumference, and the rotation is suppressed.The opposite side of the free end of the plate spring 20 is fixed to theplate member 18 a by a screw 20 a.

In this state, when power is supplied to the motor 5 through the powerfeed line 16, rotation of the sun gear 7 makes the planet gears 8revolve, and deviation between the first inner tooth gear 10 and secondinner tooth gear 11 occurs. At this time, the bearing element 12 havingthe second inner tooth gear 11 has its rotation arrested by the rotationsuppressor 19, as mentioned above. However, the first inner tooth gear10 and its integrated cylinder 3 rotate together with the cylinder 4.

At this time, the motor rotation varies depending on the difference inthe number of teeth between the first inner tooth gear and second innertooth gear, and the cylinders decelerate to a speed appropriate forfeeding paper. The rotating speed of the motor is high and its torque islow, but as the speed is reduced in this manner, adequate speed andtorque for feeding paper are obtained for the cylinders 3, 4 (that is,the cylindrical roller 2).

Due to, by the rotation of the cylindrical roller 2, a band of printingsheet 21 is conveyed in the direction of arrow 300 as shown in FIG. 2.The band of printing sheet 21 is a thermal paper, and a thermal head 22is disposed at the side opposite to the cylindrical roller 2. At thistime, along with feeding of the printing sheet 21, power is supplied tothe thermal head 22, and the printing sheet 21 is printed. The printingsheet 21 is not limited to thermal paper, but a film or a card may beused.

At the end of the printing, that is, with no power supplied to the motor5, when attempting to feed the printing sheet 21 in the direction ofarrow 300, in this embodiment, the rotation knob 19 is turned in thedirection of arrow 301 in FIG. 2. At this time, a rotating force morethan a predetermined force, which is specified by the pressing force ofthe plate spring 20 to the rotation suppressor 19 a, is applied to therotation suppressor 19 a. This rotating force is transmitted to thebearing element 12, the second inner tooth gear 11, planet gears 8coupled thereto, and the first inner tooth gear 10. Consequently, thecylindrical roller 2 rotates step by step on every side of the polygonformed on the rotation suppressor 19 a. As a result, the printing sheet21 is fed manually in the direction of arrow 300 in FIG. 2.

Along with rotation of the second inner tooth gear 11, the planet gears8 rotate and revolve around the sun gear fixed on the stopped motorshaft. Therefore, excessive force is not applied to the sun gear andmotor.

According to this embodiment, since the support shaft of the bearingelement is elastically pressed and held on the holding portion at thesecond end of the cylindrical roller, the cylindrical roller can berotated at a proper speed and torque for feeding paper by the rotatingforce of the motor. In addition, the cylindrical roller can be turnedmanually, so that the printing sheet can be fed manually. Specifically,since the outer shape of the rotation suppressor is polygonal, and theplate spring is pressed to it, the cylindrical roller rotates step bystep on each side of the polygon.

FIG. 7 and FIG. 8 show a second embodiment. Herein, a bearing element 12and a support shaft 13 coupled and integrated with a second inner toothgear 11 penetrate through a plate member 18 a having a through-hole 17as shown in FIG. 7. On the outer circumference of a flat portion 13 a ofthis support shaft 13, a columnar rotation suppressor 24 integrated witha rotation knob 19 made of synthetic resin is provided. On the outercircumference of the rotation suppressor 24, a rubber piece 25 (as anexample of friction member) is pressed by a plate spring 20, and therotation of the support shaft 13 is suppressed. The rubber piece 25 isfixed to the free end of the plate spring 20. The other end of the platespring 20 is, although not shown, fixed to the plate member 18 a or thelike in the same way as in FIG. 2.

In this configuration, due to the frictional force between the rubberpiece 25 pressed by the plate spring 20 and the rotation suppressor 24,the rotation suppressing force of the support shaft 13 is heightened. Byspecifying the type and shape of the friction member, the rotationsuppressing force can be properly set. That is, the rotating force ofthe rotation knob 19 can be adjusted. In other words, by varying theelastic force of the elastic element, the rotation starting force of thesupport shaft can be easily varied.

In the first and second embodiments, the rotation suppressor 19 a, 24 isformed integrally with the rotation knob 19 made of synthetic resin. Butas clear from the explanation so far, the rotation knob 19 is not alwaysrequired to be formed integrally with the rotation suppressor 19 a, 24.As shown in FIG. 5B or FIG. 6B, the roller device without a rotationknob may be used, and a proper rotation knob may be attached asrequired, or it may be attached to other driving elements. In addition,the rotation suppressor is not limited to synthetic resin, and may beformed of metal or other material.

FIG. 9 shows a third embodiment. The support shaft 13 of the bearingelement 12 integrated with the second inner tooth gear 11 shown in FIG.3 penetrates through a hole of a rubber bushing 26. The hole has asmaller diameter than that of the support shaft 13. The support shaft 13deforms the bush 26 elastically, and penetrates a through-hole 17. Dueto the elasticity of the bush 26, the rotation of the support shaft 13is suppressed. That is, the bush 26 adjusts the rotating force of therotation knob 19. The support shaft 13 in FIG. 9 is columnar, and doesnot have a flat portion 13 a.

In this embodiment, the rotation suppressing force of the support shaftis increased by the friction member, and by specifying the type andshape of the friction member, the rotation suppressing force can be setproperly. Moreover, since the bushing alone can generate a rotationsuppressing force on the support shaft, the structure is simple andsmaller in size.

FIG. 10 and FIG. 11 show a fourth embodiment. In FIG. 10, a small endcolumnar portion 13 b of the support shaft 13 of the bearing element 12integrated with the second inner tooth gear 11 shown in FIG. 3penetrates through a plate element 18 a having a through-hole 17. On theouter circumference of the small end columnar portion 13 b, four platesprings 27 are pressed against the columnar portion 13 b from the outercircumference.

In this embodiment, the four plate springs 27 are formed from a metaldisk plate, or preferably a steel plate for a spring as shown in FIG. 10and FIG. 11, and four notches 28 are punched out by a press and thelike. By pressing the four plate springs 27 to the small end columnarportion 13 b at equal intervals, a stable rotation suppression force isapplied to the support shaft 13. The four plate springs 27 arepreferably disposed at equal intervals of 90 degrees on the outercircumference of the small end columnar portion 13 b of the supportshaft 13. Similarly, the angle formed by the plate springs 27 is 180degrees in the case of two springs, 120 degrees in the case of threesprings, or 72 degrees in the case of five springs.

In this embodiment, by disposing a plurality of plate springs andpressing them to the support shaft from the outer circumference, therotation suppressing force on the support shaft is stabilized.

FIG. 12 and FIG. 13 show a fifth embodiment of the invention. In FIG.12, a holding portion for the support shaft 13 of the bearing element 12integrated with the second inner tooth gear 11 shown in FIG. 3 is formedby a plate member 18 a having a through-hole 17, through which a flatportion 13 a of the support shaft 13 penetrates.

Inside of the plate member 18 a, a friction member 29 having anundulated surface 30 is provided. The flat portion 13 a of the supportshaft 13 penetrates a through-hole 32 of the friction member 29. In thisstate, the friction member 29 is pressed to the inner side of the platemember 18 a by a spring 31. In this configuration, by adjusting thepressing force by the spring 31, the rotation suppressing force of thesupport shaft 13 (that is, the rotating force of the rotation knob 19)can be easily adjusted and varied.

In this embodiment, the through-hole 32 of the friction member 29 has aflat portion being the same as the flat portion 13 a of the supportshaft 13. It is formed slightly larger than the flat portion 13 a sothat the support shaft 13 may slide freely in the axial direction.Therefore, due to the pressing force of the spring 31, the undulatedsurface 30 can be securely pressed against the inner side of the platemember 18 a. At least one plane portion is required in the support shaft13 and through-hole 32 respectively, for preventing the support shaft 13from slipping relative to the friction member 29 and thereby suppressingthe rotation.

In the embodiment, by adjusting the pressing force by the spring, therotation suppressing force of the support shaft can be varied easily.

FIG. 14 to FIG. 16 show a sixth embodiment. In this embodiment, at theend of the cylindrical roller 2, a shaft portion 19 b of a rotation knob19 is fitted to the outer circumference of the support shaft 13 of thebearing element 12 at a flat end portion 13 a thereof. This shaftportion 19 b slidably penetrates a large-diameter through-hole 17 a of aplate member 18 a. This shaft portion 19 b has a gear-like engagingportion 19 c and a cylindrical sliding portion 19 d. The engagingportion 19 c engages a gear-like engaging portion 17 b on an innersurface of the through-hole 17 a of the plate member 18 a. In thisconfiguration, the shaft portion 9 b of the rotation knob 19 is slidableon the flat portion 13 a of the support shaft 13.

This portion is assembled as follows. First, as shown in FIG. 14, theshaft portion 19 b penetrates from the outside of the plate member 18 ato the inside of the through-hole 17 a, and a spring 33 abuts againstits end. A stopper ring 34 is fitted to the inner end side of the shaftportion 19 b to prevent the knob 19 from slipping off. Thus, therotation knob 19 is prevented from being slipping out of the supportshaft 13. This state is shown in FIG. 15.

At this time, the engaging portion 19 c of the shaft portion 19 b isengaged with the engaging portion 17 b of the through-hole 17 a.Therefore, the rotation of the support shaft 13 is suppressed, so thatthe cylindrical roller 2 will not be rotated by the rotation knob 19through the support shaft 13. To turn the cylindrical roller 2 by therotation knob 19, as shown in FIG. 16, the rotation knob 19 is pressedwhile compressing the sprint 33 to the left in FIG. 16. As a result, thesliding portion 19 d of the shaft portion 19 b is pushed along shaft 13until it is opposite to the engaging portion 17 b of the through-hole 17a. In this state, the cylindrical roller 2 can be rotated by therotation knob 19, and the printing sheet 21 is fed manually.

In this embodiment, by sliding the rotation knob and rotating, thecylindrical roller is turned, so that the printing sheet can be fedmanually.

A seventh embodiment of the invention is explained by referring to FIG.17 to FIG. 21. The same portions as in the prior art are identified withthe same reference numerals, and a duplicate explanation is omitted.

FIG. 17 is a sectional view of a cylindrical roller device in theembodiment of the invention. FIG. 18 is its perspective exploded view.

As shown in these Figures, a cylindrical roller 110 is formed of a metalcylindrical pipe 111 of stainless steel or the like by a two-step deepdrawing process. The outer circumference of a larger end 111A is coveredwith an elastic cylinder 112 such as silicone rubber, and a smaller end111B is fitted to a bearing 123, and is rotatably supported on a frame118.

Inside of the cylindrical roller 110, a first inner tooth gear 10 isformed, and the outer side of a planet gear 8 rotatably supported on acarrier 9 engages the first inner tooth gear 10. A bearing element 116including a second inner tooth gear 116C is arranged coaxially with thefirst inner tooth gear 10. The bearing element 116 is formed of anoil-filled sinter by forming and baking fine metal particles andimpregnating with synthetic oil or mineral oil. More specifically, theinner tooth gear 116 is shaped and arranged as follows. The outercircumference includes a protrusion 116A sliding on the innercircumference of the cylindrical roller 110, and a rotation suppressingportion 116B having a polygonal flat plane. The inner circumference hasthe second inner tooth gear 116C having a different number of teeth fromthat of the first inner tooth gear 10, and engaging the outer side ofthe planet gear 8 rotatably supported on the carrier 9.

The motor 5 is mounted on the frame 118 coaxially with the cylindricalroller 110, together with a cylindrical member 119. A sun gear 7 fixedon a rotary shaft 120 of the motor 5 is inserted into a central hole 9Aof the carrier 8, and engages the inner sides of two planet gears 8A, 8Bsupported rotatably on the carrier 9 at a predetermined interval.

The operation of the sun gear, planet gears, and two inner tooth gearsis the same as explained in the first embodiment.

One end of a controlling member 122 is fixed to the frame 118. Anelastic member 122A at the other end presses the polygonal rotatingsuppressing portion 116B provided on the outer circumference of thebearing element gear 116 with a force greater than the driving force ofthe second inner tooth gear 116C. Thus, the rotation of the second innertooth gear portion 116 is suppressed.

Further, a bearing portion 116D of the bearing element 116 is supportedby the outer circumference of the cylindrical member 119 inserted intothe frame 118.

An electronic apparatus including a printer using the roller device isexplained below by referring to FIG. 19 to FIG. 21.

FIG. 19 is a perspective view of a printer, FIG. 20 is its perspectiveexploded view, and FIG. 21 is a perspective exploded view of a frameunit of the printer. In these drawings, a roller device 129 and a frameunit 130 are combined to form a printer. The frame unit 130 includes aU-shaped base frame 131 having a bottom plate and side plates raisedupward from both sides of the bottom plate, a mounting plate 132, aprinting head 133, and a pressure spring 134 for pressing the printinghead 133 against the cylindrical roller 110 through the mounting plate132.

In this configuration, when the printing head 133 is pressed against thecylindrical roller 110 by the pressing spring 134, its force is receivedby the cylindrical member 119 fixed to the frame 118 through theprotrusion 116A of the bearing element 116. Therefore, the pressingforce is not applied to the sun gear 7 fixed to the shaft 120 of themotor 5, and the rotation of the motor 5 is transmitted appropriately tothe planet gears 8A, 8B.

In the same way as in the first embodiment, when the motor 5 rotates,the planet gears 8A, 8B revolve, and a deviation occurs between thefirst inner tooth gear 10 and second inner tooth gear 116C based on thedifference in the number of teeth.

The second inner tooth gear 116C has its rotation arrested by therotation suppressing portion 116B pressed by the elastic member 122A ofthe controlling member 122. Therefore, in the same way as in the firstembodiment, the cylindrical roller 110 having the first inner tooth gear10 is decelerated and rotated.

This principle of operation is the same as explained with respect to thefirst embodiment. Due to the rotation of the cylindrical roller 110 towhich the printing head 133 is pressed, a band of printing sheets 125disposed between the cylindrical roller 110 and the printing head 133 isconveyed. At this time, when power is supplied to the printing head 133,characters and others are printed on the printing sheet 125, and theinformation is recorded. When the motor 5 is stopped, if the userattempts to feed the printing sheet 125, the user turns the rotationknob 124 provided on the cylindrical roller 110. This force istransmitted from the first inner tooth gear 10 to the planet gears 8.This force is further transmitted to the bearing portion 116D throughthe second inner tooth gear 116C. At this time, the rotation suppressingportion 116B receives a rotating force greater than a predeterminedforce from the controlling member 122. Thus, in the same way as in thefirst embodiment, the cylindrical roller 110 rotates step by step oneach side of the polygon formed on the rotation suppressing portion116B, so that the printing sheet 125 may be fed manually. Thus,according to the embodiment, the printer is reduced in size. Since theprinter drive device is formed in a unit, it is easily assembled withthe printer device main body.

If an external force greater than a predetermined rotating force isapplied to the cylindrical roller 110, for example, by directly turningthe cylindrical roller 110 manually, or by pulling out the printingsheet 125 disposed between the cylindrical roller 110 and the printinghead 133 by force, destruction of the gearing mechanism can be avoidedby properly rotating the second inner tooth gear 116C.

Further, by forming bearing element 116 from an oil-filled sinter, thelubrication of the sliding portions is increased, and the frictionalload occurring between the bearing element 116 and cylindrical roller110 can be reduced. This is because the oil-filled sinter is impregnatedwith synthetic oil or mineral oil after forming and sintering fine metalparticles.

The inner periphery other than the inner tooth gear of the bearingelement 116 (i.e., bearing portion 116D) is supported by the outerperiphery of the cylindrical member 119 inserted in the frame 118. Thus,the pressure of the head 133 is received by the cylindrical member 119through the cylindrical roller 110 and the second inner tooth gear 116.Therefore, deflection occurring in the fitting support portions of thecylindrical roller 110 and the bearing portion 116 is decreased, so thatthe cylindrical roller 110 and head 133 may uniformly contact eachother.

The cylindrical roller 110 is composed of a two-step drawing pipe havinga large diameter and a small diameter. By supporting the smallerdiameter portion with the frame 118, the cylindrical roller 110 can besupported by the frame 118 without using different materials. Thus,according to the embodiment, a printer drive device of a small size isrealized. In FIG. 22, in the inner rear portion of a main body case 201,a control unit 202 including a direct-current power source isaccommodated as shown in FIG. 23 and FIG. 24. In the middle of the mainbody case 201, a concave accommodating portion 203 is provided. At thefront side, of the main body case 201, there is a sheet receiver 204having a head (generally called a thermal head) including a heatingelement on its top. On the front upper side of the main body case 201, alid 205 is provided so as to be opened or closed freely by a shaft 206.In the lower middle portion of the lid 205, as shown in FIG. 23 and FIG.24, a protruding wall 207 is extends downward. In the space formedbetween the protruding wall 207 and the accommodating portion 203, aroll of printing sheet 208 rotatably accommodated.

On the other hand, at both sides in the lower front portion of the lid205, a holding portion 209 is provided as shown in FIG. 25. A slit 210is provided in this holding portion 209 in the vertical direction. Inthis slit 210, a flat portion 212 a of a support shaft 212 provided atboth ends of a cylindrical roller 211 is slidably fitted. This flatportion 212 a is pressed downward by a spring 213. That is, thecylindrical roller 211 is always pressed downward by the spring 213. Thelid 205, in the closed state as shown in FIG. 22 and FIG. 23, is fixedto the main body case 210 by an engaging portion not shown.

Thus, the printing sheet 208 is held between the sheet receiver 204 andcylindrical roller 211, and is conveyed forward by rotation of thecylindrical roller 211. At this time, the printing sheet 208 is printedby the head of the sheet receiver 204. It is then discharged from afront discharge port 214 of the main body case 201 as shown in FIG. 22and FIG. 23.

The cylindrical roller 211 is the same as the roller device in the firstembodiment in its structure and operation. The support shafts 212projecting at both sides of the cylindrical roller 211 correspond tosupport shaft 13 and extended portion 149 of support element 14 as shownin FIG. 3. The support shafts 212 are slidably fitted and held in theslit 210 of the holding portion 209 of the lid 205.

As illustrated in FIG. 3 and FIG. 4, when power is supplied to the motor5 through the power feed line 16, the sun gear 7 rotates, the planetgears 8 revolve, and a deviation occurs between the first inner toothgear 10 and the second inner tooth gear 11. At this time, the secondinner tooth gear 11 has its rotation arrested, as its bearing element 12fits between the flat portion 13 a of the support shaft 13 and the slit210 of the holding portion 209. Therefore, in the same way as in thefirst embodiment, the cylindrical roller 211 including the first innertooth gear 10 is decelerated and rotated. Due to the rotation of thecylindrical roller 211, as shown in FIG. 23, a band of printing sheets 8conveyed in the direction of an arrow 300.

This operation is the same as in the first embodiment. The thermal headon the top of the sheet receiver 204 is disposed, as mentioned above, onthe surface confronting the cylindrical roller 211 opposite to the bandof printing sheet 208. When thermal paper is used as the printing sheet208, power is supplied to the thermal head as the printing sheet 208 isfed, and information is recorded on the printing sheet 208.

By recording information on the printing sheet 208, when the printingsheet 208 is consumed, as shown in FIG. 24, engagement with the mainbody case 201 formed on the lid 205 is cleared. Further, the lid 205 isopened, and a new roll of printing sheet 208 is loaded. Thus, theprinting sheet is changed smoothly. The lid 205 is closed again as shownin FIG. 23, and the information is recorded.

When changing the printing sheet 208, a clearance is kept between thecylindrical roller 211 and sheet receiver 204. After setting theprinting sheet 208, the cylindrical roller 211 is pressed to the sheetreceiver 204 side by the spring 213. Thus, the printing sheet 208 isheld between the cylindrical roller 211 and sheet receiver 204.

Thus, due to the contacting and departing operation with and from theprinting sheet 208, the relation between the cylindrical roller 211 anddriving element is constant. Therefore, the cylindrical roller 211operates securely. This is because the driving elements of thecylindrical roller 211, such as the motor 5, the sun gear 7, and theplanet gears 8 are disposed within the cylindrical roller 211.

As shown in FIG. 25, meanwhile, a guide groove 228 guides the flatportion 13 a (212 a) of the support shaft 13 (212) when closing the lid205. Therefore, the cylindrical roller 211 descends on the thermal headon the sheet receiver 204 in an adequate state.

FIG. 26 shows a ninth embodiment of the invention. A terminal 229connected to the driving element (motor 5) of the cylindrical roller 211is provided in a holding portion 209 provided in the lid 205. Further,in the main body case 201 portion opposite to this terminal 229 whenclosing the lid 205, a plug socket 230 to be fitted to the terminal 229is provided. In this embodiment, based on the opening and closing of thelid 205, the power feed route to the driving element is opened orclosed, so that a printer of a very high convenience is presented.

FIG. 27 shows a tenth embodiment of the invention. The lid 205 isdivided into two portions, and the front portion 205 a is normallyclosed as shown in FIG. 27. When changing the printing sheet 208, onlythe rear portion 205 b is opened. Thus, the leading end of the printingsheet 208 is inserted between the cylindrical roller 211 and sheetreceiver 204, and the motor 217 operates in this state. Thus, theprinting sheet 208 is conveyed to the discharge port 214 side. When thissetting is over, the rear portion 205 b of the lid 205 is also closed.

In the eighth to tenth embodiments, since the driving elements of thecylindrical roller 211 are provided within this cylindrical roller, therelation between the cylindrical roller and the driving elements isconstant. Hence, the roller operates securely.

An eleventh embodiment, a driving device is provided in a cylindricalroller, and forms a unit together with a frame having a printing head.Therefore, the cylindrical roller is compact, and can be installed invarious electronic apparatuses to be used as information recordingelement.

This embodiment is explained below while referring to FIG. 1, FIG. 2,FIG. 6, and FIG. 28. In FIG. 28, a cylindrical roller 2 is disposed on aU-shaped frame 1 made of metal plate. The cylindrical roller 2 is thesame as the roller device in the first embodiment in both structure andoperation. The frame 1 includes, as shown in FIG. 28, a bottom plate 1a. and plate members 18. 18 a extended upward from both sides. Amounting plate 1 b is bent and raised from the bottom plate 1 a.Therefore, the mounting plate 1 b is elastic. Further, a thermal head 22is fixed on the mounting plate 1 b. A support shaft 13 of thecylindrical roller 2 penetrates a circular through-hole 18 b of theplate member 18 a, and is rotatable supported in this through-hole 18 b.

A support shaft 14 a of the cylindrical roller 2 penetrates athrough-hole 18 c of the plate element 18, and its flat portion 14 b isfitted in this through-hole 18 c, so as to be supported to stop therotation. Further, on the outer circumference of the flat portion 13 aof the support shaft 13, as shown in FIG. 2, a rotation suppressor 19 aformed integrally on a rotation knob 19 made of synthetic resin isprovided. This rotation suppressor 19 a has a polygonal outercircumference (specifically, an octagonal shape) as shown in FIG. 6. Afree end of a plate spring 20 is pressed against an outer circumferenceof rotation suppressor 19 a, so that the rotation is suppressed.

The opposite side of the free end of the plate spring 20 is fixed to theplate member 18 a by of a screw 20 a.

In this state, when the motor 5 rotates, as explained in FIG. 3 and FIG.4 relating to the first embodiment, the sun gear 7 rotates, and theplanet gears 8 revolve. As a result, a deviation occurs between thefirst inner tooth gear 10 and second inner tooth gear 11. At this time,since the second inner tooth gear 11 provided on the bearing has itsrotation arrested by the rotation suppressor 19 a, as mentioned above,the first inner tooth gear 10 on the cylinder 3 is decelerated androtated together with the cylinder 4. Due to the rotation of thecylinders 3, 4 (that is due to the rotation of the cylindrical roller 2)the band of printing sheet 21 is conveyed in the direction of arrow 300as shown in FIG. 2.

This operation is the same as in the first embodiment. In other words,the cylindrical roller 2 and thermal head 22 are pressed because themounting plate 1 b is elastic as mentioned above. Hence, by rotation ofthe cylindrical roller 2, the printing sheet 21 is conveyed. When theprinting sheet 21 is a thermal paper, by feeding power to the thermalhead 22, the information is recorded.

At the end of the information recording (that is, when no power issupplied to the motor 5, in the case in which the printing sheet 21 isto be fed in the direction of arrow 300 in FIG. 1) the rotation knob 19is turned in the direction of an arrow 301 in FIG. 2.

At this time, due to the pressing force of the plate spring 20 to therotation suppressor 19 a, a rotating force greater than a predeterminedforce is applied. This rotating force is transmitted to the bearingelement 12, the second inner tooth gear 11, the planet gears 8 coupledto the second inner tooth gear 11, and the first inner tooth gear 10.Consequently, the cylindrical roller 2 rotates step by step on each sideof the polygon formed on the rotation suppressor 19 a. As a result, theprinting sheet 21 is fed manually in the direction of arrow 300 in FIG.2.

Thus, in this embodiment, forming the driving device in the cylindricalroller, a unit is formed together with the frame having the printinghead. Therefore, this roller device is compact, and when installed invarious electronic apparatuses, it can be used as information recordingelement. Further, the elastic element on the bottom plate of the framemay press the thermal head to the cylindrical roller, so that theprinting sheet can be conveyed smoothly. The mounting plate is alsoformed integrally with the frame, so that the structure may besimplified.

In the same manner as in other embodiments, by decelerating the motorrotating speed by the sun gear and planet gears, the cylindrical rollercan be rotated appropriately.

INDUSTRIAL APPLICABILITY

According to the invention, when manually turning the cylindrical rollerused in a printer or the like, damage to planet gears and the first andsecond inner tooth gears can be prevented. Therefore, the printing sheetcan be fed manually by turning the cylindrical roller manually. Alsoaccording to the invention, a printer and other electronic apparatusescapable of operating the roller securely can be obtained. Furtheraccording to the invention, a printer of a compact design is obtained.

What is claimed is:
 1. A roller device comprising: a cylindrical rollerhaving an inner circumference and a first inner tooth gear on said innercircumference; a motor including a motor shaft accommodated at a firstend of said cylindrical roller, and including a fixing portion at asecond end of said cylindrical roller; a sun gear coupled with saidmotor shaft in said cylindrical roller; a bearing element having asecond inner tooth gear and having a support shaft disposed in saidcylindrical roller, said bearing element being arranged such that arotation of said second inner tooth gear is controlled by apredetermined force; a planet gear in said cylindrical roller andengaging said sun gear, engaging said first inner tooth gear, andengaging said second tooth gear; and a bearing mechanism for supportingsaid cylindrical roller rotatably on said bearing element.
 2. The rollerdevice of claim 1, wherein said support shaft of said bearing element isdisposed at said second end of said cylindrical roller, furthercomprising a holding portion for elastically pressing and holding saidsupport shaft of said bearing element.
 3. The roller device of claim 2,further comprising a rotation knob at an end of said support shaft ofsaid bearing element.
 4. The roller device of claim 3, wherein saidholding portion comprises a plate member having a through-hole, saidsupport shaft of said bearing element extending through saidthrough-hole, further comprising an elastic member pressed to saidsupport shaft of said bearing element so as to be arranged at at leastone of an inner side and an outer side of said plate member.
 5. Theroller device of claim 3, wherein said holding portion comprises a platemember having a through-hole, further comprising a bushing fitted intosaid through-hole of said plate member, said support shaft of saidbearing element extending through a through-hole of said bushing byelastically deforming said bushing.
 6. The roller device of claim 3,wherein said holding portion comprises a plate member having athrough-hole, said support shaft of said bearing element extendingthrough said through-hole, further comprising a friction member on saidsupport shaft at at least one of an inner side and an outer side of saidplate member, and further comprising a spring for pressing said frictionmember against said plate member.
 7. The roller device of claim 2,wherein said holding portion comprises a plate member having athrough-hole, said support shaft of said bearing element extendingthrough said through-hole, further comprising an elastic member pressingagainst said support shaft of said bearing element and arranged at atleast one of an inner side and an outer side of said plate member. 8.The roller device of claim 7, further comprising a rotation suppressoron an outer circumference of said support shaft of said bearing element,an outer circumference of said rotation suppressor having a polygonalshape, said elastic member comprising a plate spring pressing againstsaid outer circumference of said rotation suppressor.
 9. The rollerdevice of claim 7, wherein said elastic member comprises a plate spring,further comprising a friction member arranged between said plate springand said support shaft such that said plate spring presses against saidsupport shaft via said friction member.
 10. The roller device of claim7, wherein said elastic member comprises a plurality of plate springsfor pressing against said support shaft.
 11. The roller device of claim2, wherein said holding portion comprises a plate member having athrough-hole, further comprising a bushing fitted into said through-holeof said plate member, said support shaft of said bearing elementextending through a through-hole of said bushing by elasticallydeforming said bushing.
 12. The roller device of claim 2, wherein saidholding portion comprises a plate member having a through-hole, saidsupport shaft of said bearing element extending through saidthrough-hole, further comprising a friction member on said support shaftat at least one of an inner side and an outer side of said plate member,and further comprising a spring for pressing said friction memberagainst said plate member.
 13. The roller device of claim 1, furthercomprising a plate member and a rotation knob having a shaft portionfitted to an outer circumference of an end of said support shaft of saidbearing element at a second end of said cylindrical roller, said shaftportion of said rotation knob slidably penetrating a through-hole ofsaid plate member, said shaft portion of said rotation knob having anengaging portion and a sliding portion, said rotation knob beingoperable to slide on said support shaft of said bearing element suchthat said engaging portion engages an inner surface of said through-holeof said plate member.
 14. The roller device of claim 1, wherein saidfirst inner tooth gear and said second inner tooth gear have a differentnumber of teeth.
 15. The roller device of claim 14, further comprising aframe for rotatably supporting at least one of said first end and saidsecond end of said cylindrical roller, said motor being fixed coaxiallywith respect to said cylindrical roller.
 16. The roller device of claim14, further comprising an elastic member for controlling a rotation ofsaid second inner tooth gear of said bearing element by pressing saidsupport shaft of said bearing element with a force greater than adriving force of said first inner tooth gear.
 17. The roller device ofclaim 14, further comprising a frame for rotatably supporting at leastone of said first end and said second end of said cylindrical roller,and further comprising a cylindrical member extending through saidframe, said bearing element having a bearing portion adjacent to saidsecond inner tooth gear, an outer circumference of said cylindricalmember being inserted into said bearing portion of said bearing elementso as to support said bearing element.
 18. The roller device of claim14, further comprising a frame for rotatably supporting at least one ofsaid first end and said second end of said cylindrical roller, saidcylindrical roller comprising a drawing pipe having a large-diameter endportion and a small-diameter end portion, said small-diameter endportion being supported by said frame.
 19. The roller device of claim 1,wherein said second inner tooth gear is formed of an oil-filled sinter.20. An electronic apparatus comprising: a main body case including anaccommodating portion for accommodating a printing sheet therein,including a plug socket, and including a lid facing said accommodatingportion, said lid having a holding portion; a sheet receiver in saidmain body case; a head for recording information on a printing sheet insaid main body case; and a roller for holding the printing sheet againstsaid sheet receiver, said roller including: a cylindrical roller havinga first end and a second end; a driving element in said cylindricalroller, said driving element including a terminal in said holdingportion of said lid, said terminal being shaped and arranged so as to befitted to said plug socket of said main body case when said lid is in aclosed position; a support element projecting from said first end ofsaid cylindrical roller; a support shaft projecting from said second endof said cylindrical roller; and a bearing mechanism at each of saidfirst end and said second end of said cylindrical roller for supportingeach of said support element and said support shaft; wherein each ofsaid support element and said support shaft is held by said holdingportion of said lid such that said cylindrical roller is operable tomove relative to said sheet receiver.
 21. The electronic apparatus ofclaim 20, wherein said holding portion includes a pressing element forpressing each of said support element and said support shaft such thatsaid cylindrical roller is pressed against said sheet receiver.
 22. Theelectronic apparatus of claim 20, wherein said head is positioned on asurface of said sheet receiver, said head including a heating element,said cylindrical roller of said roller being arranged to hold theprinting sheet against said head.
 23. The electronic apparatus of claim20, wherein said holding portion has a slit, said support shaft having aflat portion slidably fitted in said slit.
 24. The electronic apparatusof claim 20, wherein said driving element comprises a motor having amotor shaft, said roller further including: a sun gear on said motorshaft of said motor in said cylindrical roller; a planet gear engagingsaid sun gear in said cylindrical roller; a first inner tooth gear on aninner circumference of said cylindrical roller and facing said planetgear; and a bearing element having a second inner tooth gear engagingsaid planet gear, and having said support shaft projecting from a sidethereof opposite said motor.
 25. An electronic apparatus comprising: amain body case including an accommodating portion for accommodating aprinting sheet therein, and including a lid facing said accommodatingportion, said lid having a holding portion with a slit; a sheet receiverin said main body case; a head for recording information on a printingsheet in said main body case; and a roller for holding the printingsheet against said sheet receiver, said roller including: a cylindricalroller having a first end and a second end; a driving element in saidcylindrical roller; a support element projecting from said first end ofsaid cylindrical roller; a support shaft projecting from said second endof said cylindrical roller; and a bearing mechanism at each of saidfirst end and said second end of said cylindrical roller for supportingeach of said support element and said support shaft; wherein saidsupport shaft has a flat portion slidably fitted in said slit of saidholding portion, said support shaft and said support element being heldby said holding portion such that said cylindrical roller is operable tomove relative to said sheet receiver.
 26. An electronic apparatuscomprising: a main body case including an accommodating portion foraccommodating a printing sheet therein, and including a lid facing saidaccommodating portion, said lid having a holding portion; a sheetreceiver in said main body case; a head for recording information on aprinting sheet in said main body case; and a roller for holding theprinting sheet against said sheet receiver, said roller including: acylindrical roller having a first end and a second end; a motor in saidcylindrical roller, said motor having a motor shaft; a support elementprojecting from said first end of said cylindrical roller; a supportshaft projecting from said second end of said cylindrical roller; abearing mechanism at each of said first end and said second end of saidcylindrical roller for supporting each of said support element and saidsupport shaft; a sun gear on said motor shaft of said motor in saidcylindrical roller; a planet gear engaging said sun gear in saidcylindrical roller; a first inner tooth gear on an inner circumferenceof said cylindrical roller and facing said planet gear; and a bearingelement having a second inner tooth gear engaging said planet gear, andhaving said support shaft projecting from a side thereof opposite saidmotor; wherein each of said support element and said support shaft isheld by said holding portion of said lid such that said cylindricalroller is operable to move relative to said sheet receiver.
 27. Anelectronic apparatus comprising: a main body case including a lid, saidlid having a holding portion with a slit; a sheet receiver in said mainbody case; a head for recording information on a printing sheet in saidmain body case; and a roller for holding the printing sheet against saidsheet receiver, said roller including: a cylindrical roller having afirst end and a second end; a driving element in said cylindricalroller; a support element projecting from said first end of saidcylindrical roller; a support shaft projecting from said second end ofsaid cylindrical roller; and a bearing mechanism at each of said firstend and said second end of said cylindrical roller for supporting eachof said support element and said support shaft; wherein said supportshaft has a flat portion slidably fitted in said slit of said holdingportion, each of said support element and said support shaft being heldby said holding portion of said lid such that said cylindrical roller isoperable to move relative to said sheet receiver, said holding portionincluding a pressing element for pressing at least one of said supportelement and said support shaft towards sheet receiver.
 28. An electronicapparatus comprising: a main body case including a lid, said lid havinga holding portion; a sheet receiver in said main body case; a head forrecording information on a printing sheet in said main body case; and aroller for holding the printing sheet against said sheet receiver, saidroller including: a cylindrical roller having a first end and a secondend; motor in said cylindrical roller, said motor having a motor shaft;a support element projecting from said first end of said cylindricalroller; a support shaft projecting from said second end of saidcylindrical roller; a bearing mechanism at each of said first end andsaid second end of said cylindrical roller for supporting each of saidsupport element and said support shaft; a sun gear on said motor shaftof said motor in said cylindrical roller; a planet gear engaging saidsun gear in said cylindrical roller; a first inner tooth gear on aninner circumference of said cylindrical roller and facing said planetgear; and a bearing element having a second inner tooth gear engagingsaid planet gear, and having said support shaft projecting from a sidethereof opposite said motor; wherein each of said support element andsaid support shaft is held by said holding portion of said lid such thatsaid cylindrical roller is operable to move relative to said sheetreceiver, said holding portion including a pressing element for pressingat least one of said support element and said support shaft towardssheet receiver.
 29. An electronic apparatus comprising: a main body caseincluding a lid, said lid having a holding portion with a slit; a sheetreceiver in said main body case, said sheet receiver including a head ona surface thereof for recording information on a printing sheet in saidmain body case, said head including a heating element; and a roller forholding the printing sheet against said head of said sheet receiver,said roller including: a cylindrical roller having a first end and asecond end; a driving element in said cylindrical roller; a supportelement projecting from said first end of said cylindrical roller; asupport shaft projecting from said second end of said cylindricalroller; and a bearing mechanism at each of said first end and saidsecond end of said cylindrical roller for supporting each of saidsupport element and said support shaft; wherein said support shaft has aflat portion slidably fitted in said slit of said holding portion, saidsupport shaft and said support element being held by said holdingportion such that said cylindrical roller is operable to move relativeto said sheet receiver.
 30. An electronic apparatus comprising: a mainbody case including a lid, said lid having a holding portion with aslit; a sheet receiver in said main body case, said sheet receiverincluding a head on a surface thereof for recording information on aprinting sheet in said main body case, said head including a heatingelement; and a roller for holding the printing sheet against said headof said sheet receiver, said roller including: a cylindrical rollerhaving a first end and a second end; a motor in said cylindrical roller,said motor having a motor shaft; a support element projecting from saidfirst end of said cylindrical roller; a support shaft projecting fromsaid second end of said cylindrical roller; a bearing mechanism at eachof said first end and said second end of said cylindrical roller forsupporting each of said support element and said support shaft; a sungear on said motor shaft of said motor in said cylindrical roller; aplanet gear engaging said sun gear in said cylindrical roller; a firstinner tooth gear on an inner circumference of said cylindrical rollerand facing said planet gear; and a bearing element having a second innertooth gear engaging said planet gear, and having said support shaftprojecting from a side thereof opposite said motor; wherein each of saidsupport element and said support shaft is held by said holding portionof said lid such that said cylindrical roller is operable to moverelative to said sheet receiver.
 31. An electronic apparatus comprising:a main body case including a lid, said lid having a holding portion witha slit; a sheet receiver in said main body case; a head for recordinginformation on a printing sheet in said main body case; and a roller forholding the printing sheet against said sheet receiver, said rollerincluding: a cylindrical roller having a first end and a second end; adriving element in said cylindrical roller; a support element projectingfrom said first end of said cylindrical roller; a support shaftprojecting from said second end of said cylindrical roller; and abearing mechanism at each of said first end and said second end of saidcylindrical roller for supporting each of said support element and saidsupport shaft; wherein said support shaft has a flat portion slidablyfitted in said slit of said holding portion, said support shaft and saidsupport element being held by said holding portion of said lid such thatsaid cylindrical roller is operable to move relative to said sheetreceiver.
 32. An electronic apparatus comprising: a main body caseincluding a lid, said lid having a holding portion; a sheet receiver insaid main body case; a head for recording information on a printingsheet in said main body case; and a roller for holding the printingsheet against said sheet receiver, said roller including: a cylindricalroller having a first end and a second end; a motor in said cylindricalroller, said motor having a motor shaft; a support element projectingfrom said first end of said cylindrical roller; a support shaftprojecting from said second end of said cylindrical roller; a bearingmechanism at each of said first end and said second end of saidcylindrical roller for supporting each of said support element and saidsupport shaft; a sun gear on said motor shaft of said motor in saidcylindrical roller; a planet gear engaging said sun gear in saidcylindrical roller; a first inner tooth gear on an inner circumferenceof said cylindrical roller and facing said planet gear; and a bearingelement having a second inner tooth gear engaging said planet gear, andhaving said support shaft projecting from a side thereof opposite saidmotor; wherein each of said support element and said support shaft isheld by said holding portion of said lid such that said cylindricalroller is operable to move relative to said sheet receiver.
 33. Anelectronic apparatus comprising: a U-shaped frame having a bottom plateand having side plates extending upward from said bottom plate; a headon said bottom plate of said frame; and a cylindrical roller supportedbetween said side plates of said frame, said cylindrical roller having afirst end and a second end, and including: a first support shaft at saidfirst end; a motor connected to said first support shaft, and having amotor shaft; a sun gear on said motor shaft of said motor; a planet gearengaging said sun gear; a first inner tooth gear inside of saidcylindrical roller and facing said planet gear; a bearing element havinga second inner tooth gear engaging said planet gear; a second supportshaft connected to said bearing element and arranged at said second endof said cylindrical roller; and a bearing mechanism for rotatablysupporting said cylindrical roller on said first support shaft and saidsecond support shaft.
 34. The electronic apparatus of claim 33, whereinsaid head comprises a plate-shaped thermal head.
 35. The electronicapparatus of claim 34, wherein said thermal head is mounted on saidbottom plate via an elastic element.
 36. The electronic apparatus ofclaim 35, wherein said elastic element comprises a mounting plate bentand raised from said bottom plate so as to be elastic, said thermal headbeing mounted on said mounting plate.